Merge duplicate implementations of Maximum Subarray Sum

[tianyizheng02]

Feature description

There are multiple code files in this repo that all solve the maximum subarray sum problem, some of which are more or less duplicates. For example, these two files both implement a divide-and-conquer solution:

• divide_and_conquer/max_subarray_sum.py
• dynamic_programming/max_sub_array.py

And I think these two both implement a sliding-window solution:

• maths/largest_subarray_sum.py
• other/maximum_subarray.py

There may even be more implementations that I missed. At the very least, duplicates should be merged into a single file.

[ankit-gautam23]

Is this still open? I would like to look into it.

[snehanjaligvs]

@tianyizheng02 I have implemented a dynamic programming solution in the dynamic_programming/max_sub_array.py file and
also opened a pull request regarding this.
I have not done anything about the sliding window solutions.

[tianyizheng02]

Closing in favor of #8812 (didn't realize I opened a duplicate issue). Keeping the newer one because I list out the duplicates more comprehensively there.